e-beach, I'm typically building blocks of 24 to 42s and 3p, but I also have 4p and 5p boards for 20 and 25 Ah packs. So there is a lot of cells in each pack, and they are currently stuffed tightly together in the most space efficient means possible.
They will get warm during discharge, and they can get quite hot during discharge. What I don't know is a) whether this is a bad thing, and b) whether some kind of cooling system will give performance gains worthy of the weight/space cost.
Basically, if OEM battery packs are coming out with cooling, there is clearly some merit to it. But I also believe that if it adds significant weight and volume to a pack, a slightly larger pack would probably achieve the same end.
Gaston, the foil pouches are better placed to have their heat conducted away from them by means of a direct contact to the face than from the edge of the cell. That's the idea with the plates anyway. I have another idea I'll draw up soon which follows on from the different orientation of the cell groups.
I'm not the only source of ideas around here - get drawing guys!